Advanced Materials Research Vols. 503-504

Abstract: Milling of titanium alloy is usually a finishing process, therefore stable cutting process must be guaranteed at first. Temperature distributions were studied in this paper with the help of finite element method (FEM) for its significant influence on the quality of machined part. In this paper, numerical simulation was conducted by using FEM software on the whole cutting process for TC4 alloy mounting parts in an effort to investigate the metal flow behavior. The thermal simulation results obtained were compared with the cutting temperature.

Abstract: Spark plasma sintering was used to prepare Fe-Ni (Cu-41.32wt.% Cr) alloy in order to enhance the properties as inert anode for aluminum electrolysis. The effect of different sintering processes on the microstructures and properties of Fe-Ni alloy were studied by OM, SEM and EDS. The results show that the sintering process of milled powders can be divided into three stages: particles bonding, sintering neck growing, closed pole gap becoming spherical and narrowing. The SPS process of milled powders has some advantages of reacting at lower temperatures, completing faster and being densified easier than ordinary sintering. The density of Fe-Ni sample is improved and porosity is decreased as the sintering temperature is increased and holding time is extended. 1273K and 5min are the best parameters.

Abstract: Aluminum nitride thin film has been deposited on transparent SiAlON substrate by reactive magnetron sputtering. X-ray photoelectron spectroscopy patterns and raman spectra were used to analysis the phase composition of the thin film, and the surface morphology of the thin film was observed by atomic force microscope, which reveal that AlN thin film with smooth surface and columniform microstructure was formed. The fourier transform infrared spectral of the SiAlON substrate and SiAlON/AlN composition structure indicate that the AlN thin film has high transmittance above 99%, it is to say that the AlN thin film is transparent, and it nearly have no affect on the infrared transmittance of the SiAlON substrate.

Abstract: In this paper, J-integral of 3-zone inhomogeneous welded joint is calculated by use of the finite element method, and the impacts of yield strength matching factor and elastic modulus matching factor on J-integral are studied as well. The analysis results show that the yield strength matching factor affects J-integral value greatly, that is, low matching of inhomogeneous welded joint of same steel can help to improve the ductility of the welded joint and the influence of yield strength matching factor on J-integral is much greater than that of elastic modulus matching factor, so it plays a very important role in the engineering design.

Abstract: The unfired Al-Al₂O₃-MgO﹒Al₂O₃ bricks were prepared with white fused corundum, fused spinel power and metallic aluminum powder. Effects of metallic aluminum powder content (mass%=0, 2%, 4%, 6%, 8%respectively) on normal temperature physical properties and microstructure were investigated. The result revealed that by adding aluminum powder the sample showed the characteristics of “plastic molding”. New nonmetallic reinforcing phase was generated at high temperature. It could help to improve the performance at both normal temperature and high temperature.

Abstract: Because there exists a used cement mortar layer outside the recycled aggregate, there are more interfaces inside recycled concrete, which would result in recycled concrete has different properties from ordinary concrete. In this paper, the effect of such key factors for recycled concrete mix ratio as water-cement ratio, cement strength, sand rate, maximum granule diameter and gradation on the properties of concrete with recycled coarse aggregate was studied by experiment, and the some useful suggestion for mix ratio of recycled concrete was provided.

Abstract: To maintain the green and ecological features of the organic cotton knitted fabric, the extraction of sapanwood pigment and the optimization of dyeing process for the organic cotton knitted fabric are studyed in this paper. The results show that dyed by the optimized sapanwood pigment dyeing process, the washing fastness, perspiration fastness and wet rubbing fastness of the organic cotton knitted fabric reached the desired levels.

Abstract: Kenaf fiber modification, its composite material and its basic PE structure were studied by infrared spectrum and SEM in this paper, the research results show as following: 1730 cm-1 peak in Kenaf fiber clearly becomes weak and 1647 cm-1 peak reduces even disappears via KH-550 coupling treatment. The reaction intensity increases between C-O bonds in 1070 ㎝-1 and C-O-C bonds in 1160㎝-1 with coupling reaction. After KH-550 silane coupling treatment, Kenaf fiber’s C=O bond at 1750 ㎝-1 and PE composite material’s -OH bond at 1250㎝-1 weakens obviously, result in a better compatibility, which is consistent with mechanical property and SEM microstructure of composite materials.

Abstract: The temper-resistance temperature of Cr-W-Mo-V high carbon medium alloy steels is in a range at 200°C-300°C. Along with increasing C and alloy contents in particular Cr content of the steels, the temper-resistance is boost up gradually and maximal hardness arrives to 63-64HRC at temperature 200°C-250°C. When budget for quenching matrix composition and undissolved carbides, the actual quenching temperature TH is corresponding to the calculational temperature TC by phase-equilibrium thermodynamics as TH=TC + (1000°C－TC)/6.5, and roughly, the calculational temperature is less 20°C than actual temperature when quenching at 800°C-890°C. The carbides precipitation during tempering is agreement with phase equilibrium thermodynamic calculation incompletely, thereinto (Fe,Cr)3C carbide precipitation is leading at 200°C-250°C.The higher hardness at temper-resistance temperature is corresponding to tempering temperature of remnant austenitic decomposing acutely.The tempering hardness can be estimated on the basis of quenching hardness calculation. The quenching hardness value can be obtained from HC=α（1+β）/(0.00915α+0.00527), in which α is the square root of carbon content in the matrix and β is correction coefficient of solid solution strengthening.

Abstract: The purpose of the present study was to discuss the effects of local solidification time and thermal gradient on porosity content in long solidification range A201 aluminum alloy plate castings. With systematic change in the riser size, together with variation of thickness and length, were cast in different kinds of molds. The sand molds with end chill for the plate castings were made of 100% silica sand. The porosity content of A201 aluminum alloy was affected by the local solidification time and thermal gradient at same time in this study. The correlation between porosity content and any individual thermal parameter is found to be split into 2 bands, each being associated with one of the two thicknesses of plate castings. The higher the thermal gradient, the lower the porosity content was measured in the A201 aluminum alloy plate casting. And high thermal gradient with short solidification time will get lower porosity content in aluminum alloy castings